Rotary underreamer



W. N. THOMPSON ROTARY UNDERREAMER Filed Oct. 12, 1920 2 Sheets-Sheet l IIYVENTOR. 4 le/[10m 52 BY f3 ATTORN y 1,519,641 W. N. THOMPSON ROTARY UNDERREAMER F l 1 12, 1 20 '2 Sheets-Sheet 2 INVENTOR.

ATTbR EY Patented Dec. 1 6, 1924. p

ALTER n. rnomrson, or rarer,

Application file To all whom it a citizen of the United Taft, in the county of California, have invented a RotaryUnderreamer,

v of ing is a specification.

may concern: Be it-known that I, WALTER Kern and cnmroimm.

no'rAnY unnnnnnnnnn.

residing at State of new and useful which. the follow- States,

This invention relates to well boring tools and is more particularly reamers utilized for enlarging directed to underthe bore of a well to permit the lowering. of the well casing.

The object of an underreamer adapted tion with the rotary system of well drilling.

Another object is to the invention is to provide for use in connecprovide an underreamer in which the cutting elements are freely rotatable and are carried by relatively expansible earners adjustably supported onassociated with means the tool body, the carrier being for automatically translating said carriers to and yieldingly maintaining them inflexpanded relation for underreamingand adapted to be positively translated to collapsed positions for an insertion of the tool into awell or a Withdrawal of the tool therefrom.

Another object is to provide an underreamer having freely rotatable disc cutters capable of bemg separately their carriers without the other elements of the removed from disturbing any of tool.

Another object is to position the disc cutters in such relation to the their individual rotation bore as to cause wall of the well about their axes by the rotation of the tool within the well bore 1n an underreaming operation.

Among-the several other objects of the in.

vention is the provision. of adequate cooperating bearlng surfaces of body; and carrlers to maintain the carriers against displace- I ment, to withstand the which the parts may various strains to be subjected, and to guide the carriers duringtheir translation on the body;-efiicient and simple means for holding the carriers in expanded position; independent tension means translating each carrier in its automatic operation; I

replacement are exters which as parts for disc cutceedingly economical of manufacture, are of great durability and may be quickly andconveniently disconnected from orconnected such a construction and arrangement of parts as shall befvery to their carriers; and

N. THoMr'soN,

aima 1920. Serial No. 416,491.

strong-and durable, positive in operation and efficient in function.

Various other ob ects and advantages will be fully-set forth in the following descr ption of the accompanyin drawings,-wh1ch form a part of this disc o'sure,-and which illustrate a preferred form of embodiment of the invention.

Of the drawings:

Figure 1 is a front elevation of the underof the underreamer, similar to Fig. 3, showin the cutters inexpanded position.

ig. 6 is a plan section on'line 66"of Fig. 5. I

Fig. 7 is a bottom plan view of Fig. 6. Fig. 8 is an enlarged edge elevation of one of the carriers and'disc' cutters illustrating one form of disc pivot.

Fig. 9 is a similar elevation 1 second form of disc pivot.

Fig. 10 is a plan section on Fig. 9.

Fig. 11 is a detail perspective view of one of the cutter carriers looking at the inside face thereof.

With reference to the drawings, 2 designates the body proper which carries the operating elements ofthe tool, and 3' the sub which has the usual form screw-threaded head 4 for connection with the drill tubing .in' the well known manner. The lower end of the sub is recessed to provide achamber-5 with theupper portion of the chamber wall threaded and formed to provide an abutment seat 6. The body 2 "has an axial shank projecting upwardly into the chamber 5 and provided with a screwthreaded head 7 engaging of the chamber and an annular shoulder Senga of the b0 y 2 is reduced in diameter to pro vide a seat 9 andto form a boss 10 fitting into the lower end of the chamber 2 and at the base of the boss the body isg-grooved to receive a packing ring ll. When the parts the threaded wall in theseat' 6. The upper end llustrating a of tapered.

line 1a' 10 or.

'sub engages and compresses the .body 2 and are screwed together the lower edge of the packing ring into the groove to form a fluid tight joint, the boss 10 assisting in maintaining the two partsin true axial alignment. The

the sub 3 are provided with relatively aligned longitudinal ducts 12, 13, the. duct 13 communicating with the drill tubing and the duct 12 extending to thelower end of the body, the ducts entraining lubricating and .flushing fluid, such as water, from the tubing to the cutters.

The lower end of the body 2 has two longitudinal pockets or ways 14, 14 dis: posed on opposite sides of the axis of the body and of substantially square cross-sectional contour. These ways define opposed inthrust bearing surfaces 15, 15 and outthrust bearing surfaces 16, 16, the top walls of'said ways providing end thrust bearing surfaces 1 17. The outer walls of the pockets are longitudinally slotted as at 18, 18 and the medial portion of the lower end of the body between the pockets is formed toprovide beveled expanding surfaces 19, It will be seen, by reference to Fig. 6, that the pockets 14, 14 are not diametrically aligned but are disposed in substantially parallel planes on opposite sides of the longitudinal axis of the body. The purpose of this disposition will be later pointed out.

Slidable within the pockets or ways 14, 14 are cutter carriers 20, 20 each having bifurcated upper ends, and positioned between the furcations of each carrier is the lower end of a spring rod 21, each rod being attached to itscompanion carrier by a transverse pivot pin 22. The body is provided with parallel longitudinal bores forming spring chambers 23, 23 to receive coil springs 24, 24, and secondary bores 25, 25 extending through the upper walls of the pockets 14, 14 and axially aligned with the chambers 23, 23. The rods 21, through the bores 25 7 spring chambers 23, 23, said rods sliding fit in'the bores 25,25.

Each spring 24 surrounds its companion rod 21 and seats on a washer 261.00% on the rod, the washer engaging a packing ring 27 serving to prevent such fluid as mayleak past the shank head 7 from entering the way 14. The upperends of the rods 21 are threaded to receive nuts 28, 28, and are provided with transverse-cotter pins 29, 29 g the nuts from working loose.

of the springs engage loose he upper ends washers 30,30 which in turn engage the nuts, the springs exerting their tensions to urge the rods upwardly.

Each of the I,

of the pockets .14 of thebody, I large'd lower end provided with alaterally disposed bearing stud 31 (see Fig. -8) upon 21 extend upwardly described, a

cutter carriers hasa s'ulbsta-n- I 'upward movement of the Fig. 5, and transmit all inward transverse thrusts applied to the cutter, directly to the body. Likewise the outer vertical surfaces 44 of the carriers, ma be termed carrier outthrust surfaces, in t at they engage the outthrust bearing surfaces 16, 16 of the body, and the ,upper end surfaces 45 of the carriers may be termed carrier end thrust surfaces, for the reason that they engage -and transmit to the end-thrust bearing surfaces 17,17of the body all vertical thrusts to'which the cutters are subjected.

The upper end of the outer vertical sur face of each carrier is angled, as at 38, to permit the lapsing operation.

tilting of the carrier in a col- Extending laterally from the outer ve l-ti I cal surfaces of the carriers 20, 20 are key wings 40, 40 which are adapted to slide in the respective slots 18, 18 of the body, and when the carriers are in expanded position these key wings project beyond the body in position to contact the end of the casing or casing shoe .during a withdrawal of the underreamer from the well, said withdrawal causing the carriers to be lowered relative.

to the tool body and then forced inward to collapsed position. The key wings 40,40

also serve as additional means for prevent-' ing an axial twisting of the carriers in their pockets or'ways.

By reference to Figs. 7 and 11, it will be noted that the inner corners of the enlarged portions of the carriers are cut away as at 41 so as to avoid interference of the carriers, one with the other, when in collapsed positions. Figs. 9 and 10 illustrate a modified formfof journal connectionfor the cutter discs, and in this form instead of having a stud integral with the carrier, as previously detachable screw-threaded shouldered screw 42 is provided, said screw being maintained in set position by 'a set screw tapped into the body of-the carrier and engaging the threaded screw 42. I,

From the above .it will. be evident that with the cutter carriers in collapsed position as shown in Fig. 3 and with the expansion shoulders 35 engaging beneath. the be"- eled expansion surfaces 19, 19 of the body, rods 21, 21 of the springs 24, 24 will cause the expanding or portion of the wedging apart of the cutter carriers, the shoulders 35 riding outwardly and upwardly on the expansion surfaces 19, 19 of the body and the carriers then being vertically translated upwardly in the pockets or ways 14, 14, to the expanded positions shown in Fig. 5. In a collapsing operation the engagement of the well casing or casing shoe withthe key wings 40, 40 of the carriers 20, 20 will cause the carriers to be lowered relative to the tool 4 body, to collapsed or folded in position, first moving down in a straight vertical direction until the shoulders 35 reach the expansion surfaces 19, 19 and then said shoulders ride inwardly and under the surfaces 19, 19, the carriers swinging about the pivot pins 22, 22 to the collapsed positionsshown in Fig. 3. The adjacent faces of the carriers are cut away to permit them to overlap when in their collapsed position.

With reference to Fig. 7 it will be pointed out that the cutter discs 32, 32 are dispose in spaced relation and in relatively parallel planes on opposite sides of the vertical axis of the tool. That is to say,

ed in a plane approximately parallel with wall, traveling each disc is locatthe longitudinal axis of the body 2. Hence when the body 2 rotates, the edges of the discs sweep through the earth with a lateral movement. It may also be said that each cutter disc is disposed in a vertical plane X which is transversely angled relatively to a tangent y coincident to the cutting edge of the cutter and the circumference of rotation of the tool, this angle 2 being 90 less an angle greater than the angle of repose. The efiect ofthis angular disposition will be to cause the disc cutters to'rotate in the directions indicated by the arrows in Figs. 5 and 7, with the cutter edges engaging the well downwardly and inwardly to continuously present to the wall different portions of said cutting edges and to cause the cutters to wear evenly and maintain their true circular form. Any decrease of the angle 2 will result in an increase in the speed of rotation of the cutter discs.

In other words,-it maybe pointed out that if the plane of a rotary disc cutter of this character were coincident to the radius of rotation the cutter would engage the wall of the well bore with a scraping action, whereas, when positioned in a plane which is transversely angled relative to the radius of rotatio'n a cutting action is produced which has a tendencyto rotate the cutter. If we may consider that a line 8 which intersects the axial centers of the cutters designates the radial disposition of the cutters, the cutters may be said to bedisposed in planes which are angled relative thereto, that is, the cutters are disposed .in relative planes which are angularly disposed relative to the plane of their radial disposition.

In referring to the cutter discs as being ward translation,

' a plane substantially each located in a plane approximately parallel with thedOngitudinal axis of the body 2, it should be'understood that I mean to say that the plane of each disc should extend in the same general direction as the axis of the body. In order to get the best eflect it is advisableto have the plane of each disc disposed substantially parallel with this axis but it is obvious that an underreamer in which the plane of each disc merely extends in the same general direction as the axis could operate very effectively and in operating would function so that the edge of each disc would sweep in a direction lateral to the plane of the disc through the earth.

As stated above, the direction of rotation should be that indicated in Figure 7; with d with the discs and passing through the axis of the body 2.

I claim: I

I 1. A rotary underreamer having a body providing opposed ways, relatively expansible carriers slidable in said ways, cutter discs journaled on the carriers, and means for translating the carriers, the body being provided with means causing separation of the carriers during their upward-translation, the cutter discs being pos tioned in relative spaced vertical planes on opposite sides of the vertical axis of the body, each cutter disc lying in a plane substantially parallel to the plane in which the carriers move in their collapsing and exanding movement, the parts being so arranged that, when the device is reaming, if a horizontal line be drawn from the axis of the reamer to the remotest point of the cut-- ter, and a second horizontal line be drawn through the said remotest point perpendicular to the first line and extending forwardly therefrom in the direction in which the body rotates, this second line will make an obtuse angle with the the cutter.

2. A rotary underreamer having a body providing opposed ways, relatively expansible carriers slidable in said ways, cutter discs journaled on the carriers, and means for translating the carriers, the body being provided with means causing an expanding separation of the carriers during their upthe cutter discs being positioned in respective planes which are substantially parallel, each cutter disc lying in parallel to the plane in which the carriers move in their collapsing and expanding movement, the parts being so arranged that, when the device is reaming, if a horizontal line be drawn from the axis of the reamer to the remotest point of the cutter, and a second horizontal line be an expanding forwardly advancing face of drawn through the said remotest point perpendicular to the first line and extending forwardly therefrom in the direction -in which the body rotates, this second line will make an obtuse angle with the forwardly advancing face-of the cutter.

3. A rotary underreamer comprising a body having opposed slideways, carriers slidable in said ways, means for translating the carriers, the body being provided with means for transversely expanding the carriers during theiru-pward translations, and cut er discs journaled on the carriers and lying in planes substantially parallel to the direction of expansion of the carriers, the parts being so arranged that, when the device is rezhning, if a horizontal line be drawn from the axis of the reamer tothe remotest point of the cutter, and a second horizontal line be drawn through the said remotest point pegpendicular to the first line and extending orwardly therefrom in the direction in which the body rotates, this second line will make an obtuse angle with the forwardly' advancing face of the cutter.

4. A rotary underreamer comprising a body having opposed ways defining inthrust bearing'surfaces, opposite out thrust bearing surfaces, and upthrust bearing surfaces, carriers slidable in said ways, means for translating the carriers upwardly to engage the bearing surfaces an? expanding outwardly, and cutter discs jou naled on the carriers and lying in planes substantially parallel to the direction of travel of the carriers, the parts being so arranged that, when the device is reaming, if a horizontal line be drawn from the axis remotest point of the cutter, and a second horizontal line be drawn through the said remotest point perpendicular to the first line of the reamer to the body having opposed ways and intermediate expanding surfaces, carriers slidable in said ways and having expansion shoulders cooperating with the expanding surfaces, means" carriers over the expandfor translating the 7 mg shoulders to expand the carriers, and

disc cutters journaled by the carriers to move in a direction substantially parallel to the plane of their cutting edge upon expansion of the carriers, the parts being so arranged that, when the device is reaming, if a horizontal line bedrawn from the axis of the reamer to the remotest point of the cutter, and a second horizontal line be drawn through the said remotest point perpendicular to the first line and extending forwardly therefrom in the direction in which the body rotates, this second line will make an obtuse angle with'the forwardly advancing face of the cutter.

6. A rotary underreamer having a body with opposed slideways, carriers slidable in the ways and pand the carriers when upwardly translated, means for translating the carriers, and disc cutters having size of the body and journaled on the carriers, said disc cutters mounted to move with the carriers in a direction I substantially parallel to the plane of'their cutting edge.

Signed at Taft, California, this 20th day of September, 1920.

WALTER N. THOMPSON. Witnesses:

R. L. Bonus, Grins. ONEIL.

provided with surfaces to exa diameter substantially the- 

